There is a need for a water borne, solvent free polyurethane/acrylic polymer (UA) dispersion for film to film lamination of flexible packaging materials.
U.S. Pat. Nos. 3,684,758 and 3,705,164 disclose a process for making stable aqueous polymer dispersions by subjecting vinyl monomers to radical emulsion polymerization in the presence of a stable aqueous dispersion of (a) a high molecular weight cationic polyurethane which is gel-like in character and (b) a high molecular weight polyurethane containing anionic groups, respectively.
U.S. Pat. No. 4,198,330 discloses a polyurethane latex and a polymer of at least one vinyl monomer, the polymer having been obtained by free-radical polymerization of the monomer in the presence of the latex and being characterized as a hard, resinous material at temperatures below about 60.degree. C.
U.S. Pat. No. 4,644,030 discloses a method for making a stable aqueous dispersion of polymeric material comprising:
(A) producing an NCO-terminated polyurethane prepolymer in the presence of inert liquid polymerizable ethylenically unsaturated monomer material; PA1 (B) dispersing the product from (A) in water; PA1 (C) chain-extending the prepolymer in the resulting aqueous dispersion; and PA1 (D) subjecting the aqueous dispersion from (C) to vinyl addition polymerization conditions to polymerize the monomer material in-situ. PA1 (A) forming a solution of an anionic water-dispersible isocyanate-terminated polyurethane in at least one vinyl monomer; PA1 (B) dispersing the solution in an aqueous medium; PA1 (C) chain-extending the polyurethane, and either PA1 (D) adding further vinyl monomer, and PA1 (E) initiating polymerization of the vinyl monomer, or PA1 (F) initiating polymerization of the vinyl monomer, and PA1 (G) adding further vinyl monomer during polymerization. PA1 (a) forming a carboxy-containing, water-dispersible, isocyanate terminated polyurethane prepolymer; PA1 (b) adding a vinyl monomer composition which includes a polyethylenically unsaturated monomer to the prepolymer to form a prepolymer/monomer mixture; PA1 (c) adding a tertiary amine to the prepolymer/monomer mixture; PA1 (d) dispersing the prepolymer/monomer mixture in water; PA1 (e) adding an oil soluble free radical initiator and a chain-extender to the aqueous dispersion; and PA1 (f) polymerizing the vinyl monomer and completing chain extension of the prepolymer by heating the aqueous dispersion. PA1 (a) reacting a polyol and isophorone diisocyanate to consume essentially all of the polyol hydroxyl functionality; PA1 (b) adding an isocyanate-reactive compound containing a carboxylic functionality and reacting it with the isophorone diisocyanate, the amount of isophorone diisocyanate present in steps (a) and (b) being sufficient to yield an isocyanate-terminated polyurethane prepolymer having an isocyanate content of greater than 0 wt %; PA1 (c) adding at least one acrylic monomer during the step (b) prepolymer forming reaction; PA1 (d) neutralizing the carboxylic-containing prepolymer with a tertiary amine to yield a prepolymer salt/acrylic monomer mixture; PA1 (e) dispersing the prepolymer salt/monomer mixture in water; PA1 (f) adding a free-radical source and a chain-terminator/extender composition comprising a monofunctional and a difunctional amine; and PA1 (g) polymerizing the acrylic monomer and completing chain extension of the prepolymer by heating the aqueous dispersion. PA1 (a) reacting a polyol and a sufficient amount of isophorone diisocyanate in the presence of a urethane catalyst at an elevated temperature under an inert (e.g., dry air) atmosphere to consume essentially all of the polyol hydroxyl functionality; PA1 (b) adding a dihydroxyalkanoic acid and reacting it with the isophorone diisocyanate, the amount of isophorone diisocyanate also being sufficient to yield a prepolymer having an isocyanate content&gt;0 wt % and preferably&lt;6 wt %, most preferably&lt;3 wt %; PA1 (c) adding at least one low Tg polymer-forming acrylic monomer during the step (b) prepolymer reaction; PA1 (d) neutralizing the carboxylic-containing prepolymer with a tertiary amine to yield a prepolymer salt/acrylic monomer mixture; PA1 (e) dispersing the prepolymer salt/acrylic monomer mixture in water; PA1 (f) adding a free-radical source and a chain terminator and chain extender composition consisting essentially of a monofunctional amine and a difunctional amine, respectively; and PA1 (g) polymerizing the acrylic monomer and completing chain extension of the prepolymer by heating the aqueous dispersion under an inert (e.g., nitrogen) atmosphere.
Also disclosed in U.S. '030 are the resulting aqueous dispersions and their use for making films, sheets and other products.
EP 0 308 115 A2 discloses a surfactant-free aqueous polymer dispersion containing an anionic water-dispersible polyurethane and a vinyl polymer, the dispersion having been obtained by:
U.S. Pat. No. 5,173,526 discloses a method for making an aqueous polyurethane-vinyl polymer dispersion which comprises: